/**
 * Storang封装
 */
const STORAGE_KEY = 'mall';
export default {
    //存储值   
    setItem(key, value, module_name) {
        if (module_name) {
            let val = this.getItem(module_name);
            val[key] = value;
            this.setItem(module_name, val);
        } else {
            let val = this.getStorage();
            val[key] = value;
            window.sessionStorage.setItem(STORAGE_KEY, val);
        }
    },
    //获取某一个模块下面的值，例如user下面的user.name
    getItem(key, module_name) {
        if (module_name) {
            let val = this.getItem(module_name);
            if (val) return val[key]
        }
        return this.getStorage()[key]
    },
    getStorage() {
        //获取sessionStorage信息
        return JSON.parse(window.sessionStorage.getItem(STORAGE_KEY) || '{}')
    },
    chear(key, module_name) {
        let val = this.getStorage();
        if (module_name) {
            delete val[module_name][key]
        } else {
            delete val[key]
        }
        window.sessionStorage.setItem(STORAGE_KEY, val);
    }
}